The field of the disclosure relates generally to gasification, and more specifically to a system and method for providing and maintaining a flame in a gasifier during start-up.
It is known to ignite pulverized-coal burner flames by means of a pulverized-coal pilot-burner. The pilot-burner itself requires an initial ignition in order to be able to ignite a pilot-burner flame. However, coal itself is poor in ignitability, and therefore, if a certain amount of thermal energy and coal particles are not contained in a coal/oxidizer mixture used to ignite a pilot-burner, ignition does not take place at all.
In addition to using a pilot-burner flame during start-up, conventional systems also utilize a pilot-burner flame continuously throughout gasification to provide energy for a reaction/gasification. However, in addition to poor ignitability, a dry coal feed is very difficult to control during gasification start-up and throughout the gasification process. For example, dry coal may be transported by a compressible fluid into a conveyance system that is designed for normal operating conditions that consist of much higher pressure and a much higher coal flow rate than are present at start-up. Further, a feeding mechanism of coal into a transport line is very sensitive at low flow conditions. Therefore, because flow rate control and flow variation are critical to gasifier start-up, it is advantageous to use a method that is reliable in gasifier start-up.